There are many commercially available pipe coupling devices which are conventionally used to join together two pipes which have been telescopically fitted into one another to form a lap joint. The connection at the lap joint formed between the fitted pipes should be mechanically strong enough so that the pipes will not pull apart or twist relative to one another. A single clamp is commonly used to accomplish this by gripping both pipes at the lap joint. More specifically, a single clamp is commonly used to clamp the larger or outside pipe against the smaller or inside pipe. When a single clamp is used, independent of its construction, the two pipes are commonly crimped together at the lap joint to prevent them from pulling apart. This is typically accomplished by over tightening the clamp to create substantial pressure upon the pipes which essentially crushes the pipes into engagement against one another. Unfortunately, by over tightening the clamp, the overlapping segments at the lap joint become somewhat deformed. If the clamp is not crimped, relative rotation between the pipes cannot be prevented. This permits the pipes to pull apart. Once the clamp is over tightened it becomes impossible for the pipes to be disassembled for repair and/or replacement. Moreover, the pipes generally connect into a system such as e.g., a vehicle exhaust system and it becomes impossible to remove worn components from the system without replacing the entire system. In a motor vehicle exhaust system the pipes are fitted telescopically into one another and it is common to remove and replace a failed or damaged pipe with new pipe.
A dual coupling for securing a lap joint between two interconnected pipes to form a fluid tight seal is known in the prior art as is taught for example in U.S. Pat. No. 4,261,600. The dual coupling in this patent is actually a one piece assembly having two circular bands each of a different diameter designed to fit the connecting ends of the two pipes. The diameters of the bands correspond to the diameters of each of the pipes. The bands need to be precisely sized in advance to conform to the exact dimensions of the pipes and cannot be used for universal application.
Although many other pipe coupling devices are known in the prior art, none are formed from two separate U shaped clamps connected together by a welded joint with each clamp having a cradle adapted to fit over adjacent ends of two pipes interconnected to one another to form a lap joint such that continuous points of contact are made with each pipe by each separate U shaped clamp about substantially the entire 360° circumference of each pipe and with the welded joint located over the lap joint. This arrangement restricts relative rotation between the two pipes and prevents the pipes from being laterally pulled apart while at the same time permits the clamping force or pressure applied by each clamp to be substantially reduced or minimized such that deformation of the overlapping pipes at the lap joint is not necessary and thus can be easily avoided.